Field of the Invention
This invention relates to an improved aromatic polycarbonate transesterification process comprising reacting a bis(aryl)carbonate and a phenol in the presence of a transesterification catalyst containing tetraborate and/or tetraaluminate anions, the improvement wherein the catalyst species is pre-formed under equilibration reaction conditions with either a phenol or a bis(aryl)carbonate prior to initiation of the transesterification reaction.
In general, prior art including The Encyclopedia of Polymer Science, Vol. 10 (1969), Chemistry and Physics of Polycarbonates, Polymer Reviews, H. Schnell, Vol. 9, John Wiley and Sons, Inc. (1964), among other publications, including Curtius et al., Great Britain No. 1,079,822 (August 1967) reports that transesterification of aromatic diesters can be carried out in the presence of basic catalysts in the formation of high molecular weight polycarbonates.